A typical rack and pinion steering gear for a motor vehicle includes a housing, a rack bar having a rack gear thereon, and pinion head having a pinion gear thereon. The pinion head is supported on the housing for rotation as a unit with a steering hand wheel of the motor vehicle. The rack bar is connected at its opposite ends to steering knuckles of the motor vehicle and is supported on the housing for back and forth linear translation by a sleeve bearing around the rack bar and by a thrust bearing behind the rack bar opposite the pinion gear. The rack and pinion gears cooperate in converting manual effort applied at the steering hand wheel into linear thrust on the rack bar to steer the motor vehicle. Lateral thrust between the rack and pinion gears, i.e. thrust perpendicular to the rack bar, is maximum when the motor vehicle is steered at low speed and minimum when the motor vehicle is steered at high speed. Where the rack gear is a variable ratio rack gear, such lateral thrust is intensified in the middle of the rack gear where the ratio is lowest and may manifest itself as audible noise attributable to lateral separation between the rack and pinion gears when the pinion head is rotated back and forth. Lateral separation between the rack and pinion gears is usually suppressed by a thrust bearing spring which biases the thrust bearing into sliding engagement on the back of the rack bar. The bias of the thrust bearing spring is established by adjustment of a seat on the housing which adjustment is made when the steering gear is built and does not change during operation of the motor vehicle, i.e. is "passive". The spring seat is adjusted to yield a passive bias of the thrust bearing spring which suppresses lateral separation between the rack and pinion gears without at the same time creating enough friction between the rack bar and th e thrust bearing t o compromise performance characteristics of the steering gear such as returnability. However, because of the intensity of the lateral thrust when the rack gear is a variable ratio rack gear, the passive bias of the thrust bearing spring may not be sufficient to completely eliminate audible noise attributable to lateral separation between the rack and pinion gears.